Hi,

If your primary antibody is made in sheep, you need to use an anti-sheep secondary antibody, whether the primary is monoclonal or polyclonal. The fact that your primary antibody is polyclonal means that it's a mix of several antibodies recognizing different epitopes of your antigen of interest. But if they are all made in sheep, then you have to use anti-sheep secondaries to detect it.

You might be able to detect it with an anti-goat however, since sheep and goat IgG are quite similar.

Hi,

Its always a thumb rule of immune reaction either immunoblotting or immunohistochemistry or immunocytochemistry or ELISA that you have to use secondary antibody against the host of primary antibody. Because secondary antibody binds to heavy chain of primary antibody and that is host specific. One more suggestion for better results use the serum for the blocking from same species in which your secondary antibody were made. For example your seondary antibody is donkey anti-sheep. Use donkey serum for blocking and antibody dilution.

Thanks

Your question was confusing. If you are making a polyclonal antiserum in sheep, the antibody will be sheep antibody. The secondary antibody must then be anti-sheep.

Are you immunizing a sheep with an antibody from another species as the antigen to create the primary antiserum? Even so, you would still need to use an anti-sheep secondary antibody for detection, since the antibodies in the antiserum will be sheep antibodies.

It doesn't matter whether your primary antibody is polyclonal or monoclonal. The secondary antibody must be directed against the species in which the primary antibody was raised.

Thank you everyone..